Study on kinetic parameters for chlorinated polyvinyl chloride with multi‐step thermal decomposition reactions

Abstract

To investigate the multi‐step thermal decomposition characteristics of the chlorinated polyvinyl chloride (CPVC) and obtain accurate kinetic parameters characterizing its entire thermal decomposition process, the thermal decomposition behaviour of CPVC was analyzed using thermogravimetric experiments. Subsequently, the multi‐step thermal decomposition reaction of CPVC was divided into multiple single‐step reactions using the fluctuating activation energy (FAE), peak‐differentiating analysis, and a first‐order pseudo bi‐component separate‐stage model. Finally, kinetic parameters of the single‐step thermal decomposition reactions determined by the distributed activation energy model method were optimized using a particle swarm optimization algorithm, and the best multi‐step reaction decomposition method was evaluated and identified. The results indicated that there were certain differences in the single‐step reaction pathways obtained by different methods. Among them, the kinetic model based on the FAE method demonstrated the highest accuracy, with a deviation between the optimized values and experimental values of only 0.0262. The accuracy of the other two methods was slightly lower, with deviations of 0.0591 and 0.0285, respectively, but the differences among the three methods were relatively close. The precise kinetic parameters determined in this study can provide an important basis for the numerical simulation of fires and the design and optimization of fire protection systems.